Press Sauté; cook and stir bacon in Instant Pot® until crisp. Remove to paper towel-lined plate. Drain off all but 1 tablespoon drippings.
Add onion, carrots and celery to pot; cook and stir 5 minutes or until vegetables are softened. Add garlic and thyme; cook and stir 1 minute. Stir in broth and water, scraping up browned bits from bottom of pot. Add split peas, half of bacon, salt, pepper and bay leaf; mix well.
Secure lid and move pressure release valve to Sealing position. PressManual or Pressure Cook; cook at high pressure 8 minutes.
When cooking is complete, use natural release for 10 minutes, then release remaining pressure. Stir soup; remove and discard bay leaf. Garnish with remaining bacon.
Notes
NOTE: The soup may seem thin immediately after cooking, but it will thicken upon standing. If prepared in advance and refrigerated, thin the soup with water when reheating until it reaches the desired consistency.